标题： 通过非相干光生成近似理想的不可区分双光子态 显示英文标题

标题： Generation of Near-ideal Indistinguishable Two-Photon State by Incoherent Light

摘要： 高质量的量子态是先进量子信息处理的核心。光子不可区分性的程度对于从光子量子计算到精密计量的应用至关重要。两光子洪-欧-曼（HOM）干涉效应提供了一种严格的量化方法，其可见度作为光源质量的最终基准。通常，相干泵浦被认为是制备量子光源不可或缺的。因此，非相干光源在当前的量子技术中应用有限。在本工作中，我们通过频率倍增的放大自发辐射光产生的非相干光生成了不可区分的两光子态。理论分析表明，泵浦的相位随机化不会影响两光子强度干涉中的符合可见度。此外，时间非相干性进一步增强了二次谐波生成中的生成谱的对称性。在实验中，非相干泵浦的光子源表现出约60%的预告效率和超过15000的符合与偶然比。观察到的HOM干涉条纹在没有任何光谱过滤的情况下显示出99.1%的可见度，证实了光子的近理想不可区分性。我们的研究揭示了时间相干性在二阶非线性相互作用中的作用，它为利用易于获取的非相干光工程化高质量量子光源提供了一种潜在的方法。 显示英文摘要

摘要： High-quality quantum states lie at the heart of advanced quantum information processing. The degree of photon indistinguishability is critical for applications from photonic quantum computation to precision metrology. The two-photon Hong-Ou-Mandel (HOM) interference effect provides a rigorous quantification method, with its visibility serving as the ultimate benchmark for source quality. Generally, the coherent pumping is widely regarded as indispensable for the preparation of quantum sources. As a result, incoherent light sources have seen limited applications in the current quantum technologies. In this work, we generate an indistinguishable two-photon state by incoherent light generated by frequency doubling of Amplified Spontaneous Emission light. The theoretical analysis indicates that phase randomization of the pumping does not affect the coincidence visibility in two-photon intensity interference. Moreover, temporal incoherence further enhances the symmetry of the generated spectrum in second-harmonic generation. In the experiment, the incoherently pumped photon sources exhibit a heralding efficiency of approximately 60\% and a coincidence-to-accidental ratio exceeding 15000. The observed HOM interference fringes show the visibility of 99.1\% without any spectrum filtering, confirming the near-ideal indistinguishability of the photons. Our study reveals the role of temporal coherence in second-order nonlinear interactions, it provide a potential approach to use an easily accessible incoherent light for engineering high-quality quantum sources.